drivers/gpu/drm/ttm/ttm_bo_vm.c

   1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
   2 /**************************************************************************
   3  *
   4  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28 /*
  29  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  30  */
  31
  32 #define pr_fmt(fmt) "[TTM] " fmt
  33
  34 #include <drm/ttm/ttm_module.h>
  35 #include <drm/ttm/ttm_bo_driver.h>
  36 #include <drm/ttm/ttm_placement.h>
  37 #include <drm/drm_vma_manager.h>
  38 #include <linux/mm.h>
  39 #include <linux/pfn_t.h>
  40 #include <linux/rbtree.h>
  41 #include <linux/module.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/mem_encrypt.h>
  44
  45 static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo,
  46                                 struct vm_fault *vmf)
  47 {
  48         vm_fault_t ret = 0;
  49         int err = 0;
  50
  51         if (likely(!bo->moving))
  52                 goto out_unlock;
  53
  54         /*
  55          * Quick non-stalling check for idle.
  56          */
  57         if (dma_fence_is_signaled(bo->moving))
  58                 goto out_clear;
  59
  60         /*
  61          * If possible, avoid waiting for GPU with mmap_sem
  62          * held.  We only do this if the fault allows retry and this
  63          * is the first attempt.
  64          */
  65         if (fault_flag_allow_retry_first(vmf->flags)) {
  66                 ret = VM_FAULT_RETRY;
  67                 if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)
  68                         goto out_unlock;
  69
  70                 ttm_bo_get(bo);
  71                 up_read(&vmf->vma->vm_mm->mmap_sem);
  72                 (void) dma_fence_wait(bo->moving, true);
  73                 dma_resv_unlock(bo->base.resv);
  74                 ttm_bo_put(bo);
  75                 goto out_unlock;
  76         }
  77
  78         /*
  79          * Ordinary wait.
  80          */
  81         err = dma_fence_wait(bo->moving, true);
  82         if (unlikely(err != 0)) {
  83                 ret = (err != -ERESTARTSYS) ? VM_FAULT_SIGBUS :
  84                         VM_FAULT_NOPAGE;
  85                 goto out_unlock;
  86         }
  87
  88 out_clear:
  89         dma_fence_put(bo->moving);
  90         bo->moving = NULL;
  91
  92 out_unlock:
  93         return ret;
  94 }
  95
  96 static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo,
  97                                        unsigned long page_offset)
  98 {
  99         struct ttm_bo_device *bdev = bo->bdev;
 100
 101         if (bdev->driver->io_mem_pfn)
 102                 return bdev->driver->io_mem_pfn(bo, page_offset);
 103
 104         return ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT)
 105                 + page_offset;
 106 }
 107
 108 /**
 109  * ttm_bo_vm_reserve - Reserve a buffer object in a retryable vm callback
 110  * @bo: The buffer object
 111  * @vmf: The fault structure handed to the callback
 112  *
 113  * vm callbacks like fault() and *_mkwrite() allow for the mm_sem to be dropped
 114  * during long waits, and after the wait the callback will be restarted. This
 115  * is to allow other threads using the same virtual memory space concurrent
 116  * access to map(), unmap() completely unrelated buffer objects. TTM buffer
 117  * object reservations sometimes wait for GPU and should therefore be
 118  * considered long waits. This function reserves the buffer object interruptibly
 119  * taking this into account. Starvation is avoided by the vm system not
 120  * allowing too many repeated restarts.
 121  * This function is intended to be used in customized fault() and _mkwrite()
 122  * handlers.
 123  *
 124  * Return:
 125  *    0 on success and the bo was reserved.
 126  *    VM_FAULT_RETRY if blocking wait.
 127  *    VM_FAULT_NOPAGE if blocking wait and retrying was not allowed.
 128  */
 129 vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
 130                              struct vm_fault *vmf)
 131 {
 132         /*
 133          * Work around locking order reversal in fault / nopfn
 134          * between mmap_sem and bo_reserve: Perform a trylock operation
 135          * for reserve, and if it fails, retry the fault after waiting
 136          * for the buffer to become unreserved.
 137          */
 138         if (unlikely(!dma_resv_trylock(bo->base.resv))) {
 139                 /*
 140                  * If the fault allows retry and this is the first
 141                  * fault attempt, we try to release the mmap_sem
 142                  * before waiting
 143                  */
 144                 if (fault_flag_allow_retry_first(vmf->flags)) {
 145                         if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
 146                                 ttm_bo_get(bo);
 147                                 up_read(&vmf->vma->vm_mm->mmap_sem);
 148                                 if (!dma_resv_lock_interruptible(bo->base.resv,
 149                                                                  NULL))
 150                                         dma_resv_unlock(bo->base.resv);
 151                                 ttm_bo_put(bo);
 152                         }
 153
 154                         return VM_FAULT_RETRY;
 155                 }
 156
 157                 if (dma_resv_lock_interruptible(bo->base.resv, NULL))
 158                         return VM_FAULT_NOPAGE;
 159         }
 160
 161         return 0;
 162 }
 163 EXPORT_SYMBOL(ttm_bo_vm_reserve);
 164
 165 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 166 /**
 167  * ttm_bo_vm_insert_huge - Insert a pfn for PUD or PMD faults
 168  * @vmf: Fault data
 169  * @bo: The buffer object
 170  * @page_offset: Page offset from bo start
 171  * @fault_page_size: The size of the fault in pages.
 172  * @pgprot: The page protections.
 173  * Does additional checking whether it's possible to insert a PUD or PMD
 174  * pfn and performs the insertion.
 175  *
 176  * Return: VM_FAULT_NOPAGE on successful insertion, VM_FAULT_FALLBACK if
 177  * a huge fault was not possible, or on insertion error.
 178  */
 179 static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf,
 180                                         struct ttm_buffer_object *bo,
 181                                         pgoff_t page_offset,
 182                                         pgoff_t fault_page_size,
 183                                         pgprot_t pgprot)
 184 {
 185         pgoff_t i;
 186         vm_fault_t ret;
 187         unsigned long pfn;
 188         pfn_t pfnt;
 189         struct ttm_tt *ttm = bo->ttm;
 190         bool write = vmf->flags & FAULT_FLAG_WRITE;
 191
 192         /* Fault should not cross bo boundary. */
 193         page_offset &= ~(fault_page_size - 1);
 194         if (page_offset + fault_page_size > bo->num_pages)
 195                 goto out_fallback;
 196
 197         if (bo->mem.bus.is_iomem)
 198                 pfn = ttm_bo_io_mem_pfn(bo, page_offset);
 199         else
 200                 pfn = page_to_pfn(ttm->pages[page_offset]);
 201
 202         /* pfn must be fault_page_size aligned. */
 203         if ((pfn & (fault_page_size - 1)) != 0)
 204                 goto out_fallback;
 205
 206         /* Check that memory is contiguous. */
 207         if (!bo->mem.bus.is_iomem) {
 208                 for (i = 1; i < fault_page_size; ++i) {
 209                         if (page_to_pfn(ttm->pages[page_offset + i]) != pfn + i)
 210                                 goto out_fallback;
 211                 }
 212         } else if (bo->bdev->driver->io_mem_pfn) {
 213                 for (i = 1; i < fault_page_size; ++i) {
 214                         if (ttm_bo_io_mem_pfn(bo, page_offset + i) != pfn + i)
 215                                 goto out_fallback;
 216                 }
 217         }
 218
 219         pfnt = __pfn_to_pfn_t(pfn, PFN_DEV);
 220         if (fault_page_size == (HPAGE_PMD_SIZE >> PAGE_SHIFT))
 221                 ret = vmf_insert_pfn_pmd_prot(vmf, pfnt, pgprot, write);
 222 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 223         else if (fault_page_size == (HPAGE_PUD_SIZE >> PAGE_SHIFT))
 224                 ret = vmf_insert_pfn_pud_prot(vmf, pfnt, pgprot, write);
 225 #endif
 226         else
 227                 WARN_ON_ONCE(ret = VM_FAULT_FALLBACK);
 228
 229         if (ret != VM_FAULT_NOPAGE)
 230                 goto out_fallback;
 231
 232         return VM_FAULT_NOPAGE;
 233 out_fallback:
 234         count_vm_event(THP_FAULT_FALLBACK);
 235         return VM_FAULT_FALLBACK;
 236 }
 237 #else
 238 static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf,
 239                                         struct ttm_buffer_object *bo,
 240                                         pgoff_t page_offset,
 241                                         pgoff_t fault_page_size,
 242                                         pgprot_t pgprot)
 243 {
 244         return VM_FAULT_FALLBACK;
 245 }
 246 #endif
 247
 248 /**
 249  * ttm_bo_vm_fault_reserved - TTM fault helper
 250  * @vmf: The struct vm_fault given as argument to the fault callback
 251  * @prot: The page protection to be used for this memory area.
 252  * @num_prefault: Maximum number of prefault pages. The caller may want to
 253  * specify this based on madvice settings and the size of the GPU object
 254  * backed by the memory.
 255  * @fault_page_size: The size of the fault in pages.
 256  *
 257  * This function inserts one or more page table entries pointing to the
 258  * memory backing the buffer object, and then returns a return code
 259  * instructing the caller to retry the page access.
 260  *
 261  * Return:
 262  *   VM_FAULT_NOPAGE on success or pending signal
 263  *   VM_FAULT_SIGBUS on unspecified error
 264  *   VM_FAULT_OOM on out-of-memory
 265  *   VM_FAULT_RETRY if retryable wait
 266  */
 267 vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
 268                                     pgprot_t prot,
 269                                     pgoff_t num_prefault,
 270                                     pgoff_t fault_page_size)
 271 {
 272         struct vm_area_struct *vma = vmf->vma;
 273         struct ttm_buffer_object *bo = vma->vm_private_data;
 274         struct ttm_bo_device *bdev = bo->bdev;
 275         unsigned long page_offset;
 276         unsigned long page_last;
 277         unsigned long pfn;
 278         struct ttm_tt *ttm = NULL;
 279         struct page *page;
 280         int err;
 281         pgoff_t i;
 282         vm_fault_t ret = VM_FAULT_NOPAGE;
 283         unsigned long address = vmf->address;
 284         struct ttm_mem_type_manager *man =
 285                 &bdev->man[bo->mem.mem_type];
 286
 287         /*
 288          * Refuse to fault imported pages. This should be handled
 289          * (if at all) by redirecting mmap to the exporter.
 290          */
 291         if (bo->ttm && (bo->ttm->page_flags & TTM_PAGE_FLAG_SG))
 292                 return VM_FAULT_SIGBUS;
 293
 294         if (bdev->driver->fault_reserve_notify) {
 295                 struct dma_fence *moving = dma_fence_get(bo->moving);
 296
 297                 err = bdev->driver->fault_reserve_notify(bo);
 298                 switch (err) {
 299                 case 0:
 300                         break;
 301                 case -EBUSY:
 302                 case -ERESTARTSYS:
 303                         return VM_FAULT_NOPAGE;
 304                 default:
 305                         return VM_FAULT_SIGBUS;
 306                 }
 307
 308                 if (bo->moving != moving) {
 309                         spin_lock(&ttm_bo_glob.lru_lock);
 310                         ttm_bo_move_to_lru_tail(bo, NULL);
 311                         spin_unlock(&ttm_bo_glob.lru_lock);
 312                 }
 313                 dma_fence_put(moving);
 314         }
 315
 316         /*
 317          * Wait for buffer data in transit, due to a pipelined
 318          * move.
 319          */
 320         ret = ttm_bo_vm_fault_idle(bo, vmf);
 321         if (unlikely(ret != 0))
 322                 return ret;
 323
 324         err = ttm_mem_io_lock(man, true);
 325         if (unlikely(err != 0))
 326                 return VM_FAULT_NOPAGE;
 327         err = ttm_mem_io_reserve_vm(bo);
 328         if (unlikely(err != 0)) {
 329                 ret = VM_FAULT_SIGBUS;
 330                 goto out_io_unlock;
 331         }
 332
 333         page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
 334                 vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node);
 335         page_last = vma_pages(vma) + vma->vm_pgoff -
 336                 drm_vma_node_start(&bo->base.vma_node);
 337
 338         if (unlikely(page_offset >= bo->num_pages)) {
 339                 ret = VM_FAULT_SIGBUS;
 340                 goto out_io_unlock;
 341         }
 342
 343         prot = ttm_io_prot(bo->mem.placement, prot);
 344         if (!bo->mem.bus.is_iomem) {
 345                 struct ttm_operation_ctx ctx = {
 346                         .interruptible = false,
 347                         .no_wait_gpu = false,
 348                         .flags = TTM_OPT_FLAG_FORCE_ALLOC
 349
 350                 };
 351
 352                 ttm = bo->ttm;
 353                 if (ttm_tt_populate(bo->ttm, &ctx)) {
 354                         ret = VM_FAULT_OOM;
 355                         goto out_io_unlock;
 356                 }
 357         } else {
 358                 /* Iomem should not be marked encrypted */
 359                 prot = pgprot_decrypted(prot);
 360         }
 361
 362         /* We don't prefault on huge faults. Yet. */
 363         if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && fault_page_size != 1) {
 364                 ret = ttm_bo_vm_insert_huge(vmf, bo, page_offset,
 365                                             fault_page_size, prot);
 366                 goto out_io_unlock;
 367         }
 368
 369         /*
 370          * Speculatively prefault a number of pages. Only error on
 371          * first page.
 372          */
 373         for (i = 0; i < num_prefault; ++i) {
 374                 if (bo->mem.bus.is_iomem) {
 375                         pfn = ttm_bo_io_mem_pfn(bo, page_offset);
 376                 } else {
 377                         page = ttm->pages[page_offset];
 378                         if (unlikely(!page && i == 0)) {
 379                                 ret = VM_FAULT_OOM;
 380                                 goto out_io_unlock;
 381                         } else if (unlikely(!page)) {
 382                                 break;
 383                         }
 384                         page->index = drm_vma_node_start(&bo->base.vma_node) +
 385                                 page_offset;
 386                         pfn = page_to_pfn(page);
 387                 }
 388
 389                 /*
 390                  * Note that the value of @prot at this point may differ from
 391                  * the value of @vma->vm_page_prot in the caching- and
 392                  * encryption bits. This is because the exact location of the
 393                  * data may not be known at mmap() time and may also change
 394                  * at arbitrary times while the data is mmap'ed.
 395                  * See vmf_insert_mixed_prot() for a discussion.
 396                  */
 397                 if (vma->vm_flags & VM_MIXEDMAP)
 398                         ret = vmf_insert_mixed_prot(vma, address,
 399                                                     __pfn_to_pfn_t(pfn, PFN_DEV),
 400                                                     prot);
 401                 else
 402                         ret = vmf_insert_pfn_prot(vma, address, pfn, prot);
 403
 404                 /* Never error on prefaulted PTEs */
 405                 if (unlikely((ret & VM_FAULT_ERROR))) {
 406                         if (i == 0)
 407                                 goto out_io_unlock;
 408                         else
 409                                 break;
 410                 }
 411
 412                 address += PAGE_SIZE;
 413                 if (unlikely(++page_offset >= page_last))
 414                         break;
 415         }
 416         ret = VM_FAULT_NOPAGE;
 417 out_io_unlock:
 418         ttm_mem_io_unlock(man);
 419         return ret;
 420 }
 421 EXPORT_SYMBOL(ttm_bo_vm_fault_reserved);
 422
 423 vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
 424 {
 425         struct vm_area_struct *vma = vmf->vma;
 426         pgprot_t prot;
 427         struct ttm_buffer_object *bo = vma->vm_private_data;
 428         vm_fault_t ret;
 429
 430         ret = ttm_bo_vm_reserve(bo, vmf);
 431         if (ret)
 432                 return ret;
 433
 434         prot = vma->vm_page_prot;
 435         ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1);
 436         if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
 437                 return ret;
 438
 439         dma_resv_unlock(bo->base.resv);
 440
 441         return ret;
 442 }
 443 EXPORT_SYMBOL(ttm_bo_vm_fault);
 444
 445 void ttm_bo_vm_open(struct vm_area_struct *vma)
 446 {
 447         struct ttm_buffer_object *bo = vma->vm_private_data;
 448
 449         WARN_ON(bo->bdev->dev_mapping != vma->vm_file->f_mapping);
 450
 451         ttm_bo_get(bo);
 452 }
 453 EXPORT_SYMBOL(ttm_bo_vm_open);
 454
 455 void ttm_bo_vm_close(struct vm_area_struct *vma)
 456 {
 457         struct ttm_buffer_object *bo = vma->vm_private_data;
 458
 459         ttm_bo_put(bo);
 460         vma->vm_private_data = NULL;
 461 }
 462 EXPORT_SYMBOL(ttm_bo_vm_close);
 463
 464 static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
 465                                  unsigned long offset,
 466                                  uint8_t *buf, int len, int write)
 467 {
 468         unsigned long page = offset >> PAGE_SHIFT;
 469         unsigned long bytes_left = len;
 470         int ret;
 471
 472         /* Copy a page at a time, that way no extra virtual address
 473          * mapping is needed
 474          */
 475         offset -= page << PAGE_SHIFT;
 476         do {
 477                 unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
 478                 struct ttm_bo_kmap_obj map;
 479                 void *ptr;
 480                 bool is_iomem;
 481
 482                 ret = ttm_bo_kmap(bo, page, 1, &map);
 483                 if (ret)
 484                         return ret;
 485
 486                 ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
 487                 WARN_ON_ONCE(is_iomem);
 488                 if (write)
 489                         memcpy(ptr, buf, bytes);
 490                 else
 491                         memcpy(buf, ptr, bytes);
 492                 ttm_bo_kunmap(&map);
 493
 494                 page++;
 495                 buf += bytes;
 496                 bytes_left -= bytes;
 497                 offset = 0;
 498         } while (bytes_left);
 499
 500         return len;
 501 }
 502
 503 int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
 504                      void *buf, int len, int write)
 505 {
 506         unsigned long offset = (addr) - vma->vm_start;
 507         struct ttm_buffer_object *bo = vma->vm_private_data;
 508         int ret;
 509
 510         if (len < 1 || (offset + len) >> PAGE_SHIFT > bo->num_pages)
 511                 return -EIO;
 512
 513         ret = ttm_bo_reserve(bo, true, false, NULL);
 514         if (ret)
 515                 return ret;
 516
 517         switch (bo->mem.mem_type) {
 518         case TTM_PL_SYSTEM:
 519                 if (unlikely(bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
 520                         ret = ttm_tt_swapin(bo->ttm);
 521                         if (unlikely(ret != 0))
 522                                 return ret;
 523                 }
 524                 /* fall through */
 525         case TTM_PL_TT:
 526                 ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
 527                 break;
 528         default:
 529                 if (bo->bdev->driver->access_memory)
 530                         ret = bo->bdev->driver->access_memory(
 531                                 bo, offset, buf, len, write);
 532                 else
 533                         ret = -EIO;
 534         }
 535
 536         ttm_bo_unreserve(bo);
 537
 538         return ret;
 539 }
 540 EXPORT_SYMBOL(ttm_bo_vm_access);
 541
 542 static const struct vm_operations_struct ttm_bo_vm_ops = {
 543         .fault = ttm_bo_vm_fault,
 544         .open = ttm_bo_vm_open,
 545         .close = ttm_bo_vm_close,
 546         .access = ttm_bo_vm_access,
 547 };
 548
 549 static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_bo_device *bdev,
 550                                                   unsigned long offset,
 551                                                   unsigned long pages)
 552 {
 553         struct drm_vma_offset_node *node;
 554         struct ttm_buffer_object *bo = NULL;
 555
 556         drm_vma_offset_lock_lookup(bdev->vma_manager);
 557
 558         node = drm_vma_offset_lookup_locked(bdev->vma_manager, offset, pages);
 559         if (likely(node)) {
 560                 bo = container_of(node, struct ttm_buffer_object,
 561                                   base.vma_node);
 562                 bo = ttm_bo_get_unless_zero(bo);
 563         }
 564
 565         drm_vma_offset_unlock_lookup(bdev->vma_manager);
 566
 567         if (!bo)
 568                 pr_err("Could not find buffer object to map\n");
 569
 570         return bo;
 571 }
 572
 573 static void ttm_bo_mmap_vma_setup(struct ttm_buffer_object *bo, struct vm_area_struct *vma)
 574 {
 575         vma->vm_ops = &ttm_bo_vm_ops;
 576
 577         /*
 578          * Note: We're transferring the bo reference to
 579          * vma->vm_private_data here.
 580          */
 581
 582         vma->vm_private_data = bo;
 583
 584         /*
 585          * We'd like to use VM_PFNMAP on shared mappings, where
 586          * (vma->vm_flags & VM_SHARED) != 0, for performance reasons,
 587          * but for some reason VM_PFNMAP + x86 PAT + write-combine is very
 588          * bad for performance. Until that has been sorted out, use
 589          * VM_MIXEDMAP on all mappings. See freedesktop.org bug #75719
 590          */
 591         vma->vm_flags |= VM_MIXEDMAP;
 592         vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
 593 }
 594
 595 int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
 596                 struct ttm_bo_device *bdev)
 597 {
 598         struct ttm_bo_driver *driver;
 599         struct ttm_buffer_object *bo;
 600         int ret;
 601
 602         if (unlikely(vma->vm_pgoff < DRM_FILE_PAGE_OFFSET_START))
 603                 return -EINVAL;
 604
 605         bo = ttm_bo_vm_lookup(bdev, vma->vm_pgoff, vma_pages(vma));
 606         if (unlikely(!bo))
 607                 return -EINVAL;
 608
 609         driver = bo->bdev->driver;
 610         if (unlikely(!driver->verify_access)) {
 611                 ret = -EPERM;
 612                 goto out_unref;
 613         }
 614         ret = driver->verify_access(bo, filp);
 615         if (unlikely(ret != 0))
 616                 goto out_unref;
 617
 618         ttm_bo_mmap_vma_setup(bo, vma);
 619         return 0;
 620 out_unref:
 621         ttm_bo_put(bo);
 622         return ret;
 623 }
 624 EXPORT_SYMBOL(ttm_bo_mmap);
 625
 626 int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 627 {
 628         ttm_bo_get(bo);
 629         ttm_bo_mmap_vma_setup(bo, vma);
 630         return 0;
 631 }
 632 EXPORT_SYMBOL(ttm_bo_mmap_obj);